Improvement in inks for writing



UNITED STATES PATENT OEEIcE.

ISIDOR POPPER, or PHILLIPSBURG, NEW JERSEY.

IMPROVEMENT IN INKS FOR WRITING.

. Specification forming part of Letters Patent No. 132,102, dated October 8, 1872.

To all whom it may concern:

Be it known that I, Isrnon POPPER, of Phillipsburg, in the county of Warren and State of New .Jersey, have invented a new and Improved Compound for Indelible Ink; and I do hereby declare the following to be a full, clear, and exact descriptionthereof, which will enable those skilled in the art to make and use the same.

This compound relates to an ink or writingflnid which, when applied on writing-paper, cannot be removed without destroying the texture of the paper or leaving a mark which bears witness that the writing has been tampered with. My compound consists of indigo, spirit of hartshorn, carbon, (by preference lampblack,) gum arabic, glycerinc, and water; and these ingredients are mixed together in about the following proportion: Indigo, four parts, by weight; spirits of hartshorn, thirty parts; lamp-black, or other equivalent carbon, ten

- parts; gum arabic, six parts; glycerine, thirty parts; water, fifty parts. After these ingredients have been thoroughly and intimate- I ly mixed, the ink or writing-fluid is put up in suitable bottles ready for the market.

My ink is intended particularly for the purpose of writing bank-checks, drafts, or other documents of value, since words, figures, or other signs or characters produced by my ink on writing-paper cannot be removed without producing marks showing that an attempt has been made to alter the check or other document.

I do not claim, separately, either of the in- 

